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Polymorphism - an array of different objects
this example from a Well House Consultants training course
Source code: Trevor.java Module: J050
public class Trevor {
/* We're setting up an array of different objects - we say that the array holds objects of the base class type, and we can then store into it any objects of the class or of subclasses (and as Peter is abstract, i.e. incomplete, they must all be subclasses in this case). When we than call getopo or getpass (or any other method), our JVM will work out which particular flavout of getopo or getpass it has to run, based on the object type in the current element of the array trowbridge. */ public static void main (String [] args) { // Setting up an array to hold anything of type Peter // (probably Rolfs and Steves!) Peter [] trowbridge = new Peter[4]; trowbridge[0] = new Rolf("First Great Western",75,3,60); trowbridge[1] = new Rolf("South West Trains",72,5,80); trowbridge[2] = new Steve("First Avon and Somerset",61,30); trowbridge[3] = new Steve("Faresaver",21,20); for (int k=0; k<trowbridge.length; k++) { String runby = trowbridge[k].getopo(); int crush = trowbridge[k].getpass(); System.out.println(runby + " will carry " + crush + " people"); } } } /* ------------ Sample Output -------------- Dorothy-2:java grahamellis$ java Trevor First Great Western will carry 225 people South West Trains will carry 360 people First Avon and Somerset will carry 61 people Faresaver will carry 21 people Dorothy-2:java grahamellis$ */ Learn about this subject
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